1. Field of the Invention
The present invention relates to an illumination device and method, and an apparatus for image taking. More particularly, the present invention relates to an illumination device and method, and an apparatus for image taking, in which a color of illuminating light can be changed easily in a simple structure.
2. Description Related to the Prior Art
Cameras of various types are known, including a photographic camera with silver halide, a digital still camera and the like. A flash device is incorporated in some of the cameras for night photography, rear light photography and other purposes. The flash device of the known type has a main capacitor and a discharge tube or xenon tube which is discharged with power from the main capacitor. However, the discharge type has problems in that waiting time is required for charging to cause difficulty in consecutive image taking, and that a very low shutter speed is unsuitable according to short emission of light as long as several milliseconds. Also, a size of the main capacitor is somewhat large and is inconsistent to reduction of the size of the camera body. Spectral distribution of the emitted light of the flash device is near to that of daylight, so that an image of an unsuitable color is created.
There are recently suggested flash devices in which light emitting diodes (LEDs) with high brightness are used. Such flash devices are disclosed in, for example, U.S. Pat. No. 7,106,378 (corresponding to JP-A 2002-116481), JP-A 2006-139297, JP-A 2005-121872 and JP-A 2006-108970. It is possible not to use a main capacitor owing to the use of the LEDs. Also, consecutive image taking is possible. A body of the camera can be compact with a reduced size. Furthermore, light can be emitted continuously, to enable operation of a shutter with a very slow shutter speed.
U.S. Pat. No. 7,106,378 (corresponding to JP-A 2002-116481) and JP-A2006-139297 disclose a flash device in which LEDs of three colors are used to change the illuminating color. An image can be picked up with a suitable color as light can be emitted with the color adjusted for the relevant condition.
However, a problem remains in LEDs which are uneven characteristically in relation to the quality. Control of the LEDs of the three color according to U.S. Pat. No. 7,106,378 (corresponding to JP-A 2002-116481) and JP-A 2006-139297 is difficult. There is a problem in the cost for the purpose of keeping high precision in the manufacture.
JP-A 2005-121872 discloses suppression of influence of unevenness between LEDs in relation to the quality, but does not suggest a construction in which the illuminating color is changeable. JP-A 2006-108970 discloses a construction in which a light amount is changeable, but does not disclose changeable illuminating color.